1. Field of the Invention
The present invention relates to an implosion-resistant band for protecting a cathode-ray tube from implosion, and a cathode-ray tube having such an implosion-resistant band.
2. Description of the Prior Art
Heretofore, as shown in FIG. 1 of the accompanying drawings, a conventional cathode-ray tube comprises a tube body 4 composed of a screen panel 1, a funnel 2, and a neck 3, and an annular implosion-resistant band 5 wound around the screen panel 1 under certain tension for protecting the tube body 4 from implosion. The conventional implosion-resistant band 5 comprises an annular metallic frame or band element 6 and a plurality of holders 7 welded to respective four corners thereof that are snugly fitted respectively over the corners of the screen panel 1. When the cathode-ray tube is placed in a housing such as a television set cabinet, for example, the holders 7 are fastened to the cabinet to support the cathode-ray tube securely in the cabinet.
The implosion-resistant band 5 is usually shrink-fitted over the screen panel 1. More specifically, the band element 6 is first heated to expand its bore, and then put around the screen panel 1. Thereafter, the band element 6 is rapidly cooled so that it is contracted and clamped firmly around the screen panel 1.
As shown in FIG. 2, each of the holders 7 that are welded respectively to the four corners of the band element 6 comprises a flange 9 held flatwise against and spot-welded to one of the corners at three spots P, and an attachment arm 10 extending perpendicularly from one edge of the flange 9 and having an attachment hole 10a for attaching the holder 7 to the cabinet.
In FIG. 1, the annular band element 6 has a marginal edge folded over on itself, providing a partial double-walled band structure. The holders 7 are welded to the portion of the annular band element 6 which is not folded over.
For shipment of implosion-resistant bands of the conventional design, they cannot be stacked one upon another as they tend to collapse during shipment. Therefore, the implosion-resistant bands should be packaged one by one and with care exercised not to deform them. The efficiency of shipment of implosion-resistant bands is poor as each implosion-resistant band is required to be packaged individually.
Unpackaging implosion-resistant bands and then supplying unpackaged implosion-resistant bands for the manufacture of cathode-ray tubes have been inefficient because these processes have been manually carried out.